DESCRIPTION (Applicant's Abstract) The goal of our proposed research program is to extend the function and improve the reliability of neural prostheses through the development of selective stimulation tools that allow a single nerve-based electrode to replace multiple muscle-based electrodes. The technology, which has been explored in both chronic animal and human experiments, takes advantage of the topographical organization of nerve fibers in a nerve trunk. Extensive research has shown that it is possible to selectively activate nerve fibers in discrete regions of a nerve trunk through control and steering of the excitatory field created within the electrode. The Field Steering Technique requires multicontact self-sizing spiral nerve cuff electrodes manufactured with four radially spaced monopoles, and a stimulator that allows each electrode contact to act as either an anode or cathode and allows multiple channels to trigger simultaneously. The electrodes required by the technique are currently available to researchers who want to advance their projects using this technology. However, when asked if the stimulator required is also available, we must now answer "no." With the project described in this application, we intend to design an implantable stimulator that will meet the clinical demand for improved methods of neural activation. In Phase I, feasibility will be demonstrated through circuit design, prototypes, and extensive benchtop testing. In Phase II, the implantable version will be built and chronic in vivo testing will be performed. PROPOSED COMMERCIAL APPLICATION: Neural prostheses are used to activate efferent nerves to restore motor function or to activate afferent nerves to provide sensory information to the central nervous system. A variety of neuroprosthetic systems have been or are currently under development for use by individuals with a wide range of neurological and physical impairments. The Field Steering Technique allows a single nerve-based electrode to replace multiple muscle-based electrodes, while extending the function and improving the reliability of the neural prostheses. An implantable stimulator is the key for commercial application of the technology.